Truck tail-gate lift



y 14, 1940- c. WLVAN BLARcoM ET AL 2.200.436

TRUCK TAIL-GATE LIFT Filed Aug. 6, 1937 4 Sh ets-Sheet l May 14, 1940-c. w. VAN BLARCOM EIAL TRUCK TAIL-GATE LIFT Filed Aug. 6, 1937 4Sheets-Sheet 2 y c. w. VAN BLARcoM ET AL 2.200.436

TRUCK TAIL-GATE LIFT Filed Aug. 6, 1957 4 Sheets-Sheet 4 I II y.

. Patented May 14, 1940 UNITED STATES 2,200,436 TRUCK TAIL-GATE LIFTCharles W. Van Blarcom and William A. Harris.

" Boonton, N. J.

Application August 6, 1937, Serial No. 157,802

6 Claims.

Our invention relates to an improvement in truck tail-gate lifts.

The object is to provide hydraulic means for raising and lowering gates,such as tail-gates or v tail-boards 'of trucks, vans and the like, andthe invention consists in means for lowering the tailate or tail-boardfrom the fioor level of the vehicle to which it is applied to theground, and for raising it from the lowered position to normal.

With theforegoing objectv in view, this invention consists in featureswhich will be specifically described'and set forth in the followingspecification. 1 e

In the accompanying drawings: :F'ig. 1 is a view in perspective}.

Fig. .2 is a rear View partly initra tical section;- r

Fig. 3 is a longitudinal section ofthrear end of a truck showing partsin elevation; Fig. 4 is a horizontal section showing the hydraulicreservoir, pump, piping and connected parts in dotted lines, and thegate in full lines;

Fig. 5 isan enlarged vertical section through the valve 21 andspring-controlled valve 28 to the one of the hydraulic cylinders; and

.Figs. 6, ,7 and 8 are detail sectional views showing the cylinders,anti-friction guide-rollers and connected parts.

The letter A representsthe rear end of a truck 1 or van, and the numerall, the end-gate. The

end-gate I is hinged to a movable sill 2, and a chain or other means 3affords support at each end to maintain its horizontal position when inoperation, and to permit it to swing on its hinge 4 and to permit'it tobe raised to vertical position when not in use.

The numeral 5 represents the hydraulic cylinders. One is stationed ineach rear comer of the vehicle, and they are fixed in place by braces 6or other suitable means. Columns 1 are located in each rear cornerparallel with the cylinders, and preferably just at the rear thereof,and their lower ends are connected withthe. sill 2. These columnsareguide'd; in their up and down movement by brackets 8 which embracethe cylinders and carry the anti-friction guiderollers 9 as viewed indetail in Figs. 6, 7 and 8. I

The cylinders preferably extend below the floor Ill of the vehicle andcarry guide-rollers II against which the columns I move when lowered asindicated in Fig. 3.

Pistons l2 are fitted to the cylinders, and extending upwardly therefromthrough the cylinders are the piston rods I3.

A head I4 is secured to the top of each bracket 8,. and each headv isprovided with an arm I5 which extends over and in the path of the pistonI3, see Figs. 5, 6 and 7, and a bolt I6 rigidly secures the brackets 8to the columns I. The'upper ends of the cylinders are slotted down asshown at H a distance equivalent to the 5 range of movement of the gatel to afiord the required clearance for the arm I5 which moves up anddown therein, and is guided thereby.

A reservoir R is-filled through a filler I9 (see Fig. 4), and a pump Pcirculates the fluid through 10 the pipe' system. The reservoir R, pumpP, and

the pipe system are indicated in dotted lines in Fig. 4. The pump isdriven from the power plant (not shown) through the shaft 20, and thefluid from the reservoir is supplied to the cylinders by pipe 22 andbranches 23 discharging preferably in the lower ends of the-cylinders,

Each cylinder is provided with an overflow pipe 24, the upper end ofwhich is beyond the highest v point of the piston stroke and below theslot IL,

and these overflow'pipes lead back to a common pipe 25 which dischargesinto .the reservoir R. A pipe 26 from the pump forms a circuit throughpipe 22, and a return pipe 29 leads back tothe 25 reservoir, and thepump is supplied through a pipe 30 extending from the reservoir to thepump.

These valves are controlled, and the end-gate is operated, by themechanism which will now be described: 30

A rock-shaft 3| extends across the rear of the vehicle and is turned. bythe operator by the removable handle 32, so that it can be operated fromeither side of the vehicle. The sill 2 normally rests on a slidingspring-actuated bolt 33.

This is connected by means of a chain or cable 34 to a rocker 35 whichis pivoted to a bracket 36 by a pin 31, and a connecting-bar 38 extendsfrom the rocker-35 to the crank-arm 55 secured on the rock-shaft 3|.Levers 39 secured to the rock-shaft 3| are connected by connecting-rods40 and 4| to the valves 21- and 28 respectively, all of which isillustrated in flull lines in Fig. 3 1 and in dotted lines inFig. 4. Thenumeral 42 is a check-valve.

- 45 Operation.--To move the gate, the power operator connects the powertake-off with'thepump by throwing a shaft lever in the cab. When thisshall have been done, the pump P. which is directly connected with. thepower take-01f shaft begins to function, drawing fluid from thereservoir R and forcing it through the pipe 26 and spring-controlledvalve' 28 which is normally open through the pipe 29 back to thereservoir, that is to say the fluid is circulated from reservoir to pumpthrough pipe 3|! and back through the valve 28 to the reservoir. Thetail-gate i is lowered to horizontal, where it is supported by thechains 3.

In order to lower the gate from the truck floor level to the street, theoperator turns the handle 32. This draws the spring-actuated bolts 33,and through the connecting rod 4| the valve 21 is opened. This permitsthe fluid to run out of the cylinders 5 through the pipes 22, 23 and 29back to the reservoir R. This lowers the piston i 2 in the cylinders,and the tail-gate i, which is indirectly connected thereto through thepiston-rods i3 and the arms I 5 and the columns 1.

The speed of operation may be controlled by the size of the orifice ofthe pipes, or, if desired, by a special adjusting valve (not shown)which might be employed in the vicinity of the valve 21, or bythrottling-valve 21 by means of control handle 32. The speed isregulated by the operator according to the load.

During raising as well as lowering, one or several times, the pump P isconnected through the power take-off to the truck motor. The pressurerelief valve 44 (see Fig. 4) and by-pass 45 are provided to permitstalling and insure against damage.

To raise the gate from the lower position indicated in dotted lines inFig. 3, the car operator turns the shaft 3| by means of removable handle32, thereby closing valve 28. This forces fluid through the check-valve42, thence through the pipe 22 and branches 23 to the cylinders 5, Thisforces the pistons i3 upward, and as the arms l5 are in their path andthese are connected through the heads II to the brackets 8 secured tothe columns I, the latter are raised, carrying with them the sill 2 towhich the tail-gate l is hinged. When the end gate has struck againstthe bolts 33 and stops located on truck floor, the control handleautomatically returns to a neutral or vertical position.

From the foregoing, it will be observed that the cylinders perform adouble function, the lower ends being used for power, and the entirelength forming guides for the movable columns I which carry theend-gate, and the lowerends of the cylinders being provided withanti-friction rollers to form guides and lateral supports for thecolumns.

As it has been pointed out, turning the rockshaft 3| toward the rearopens the spring-actuated valve 28, and the spring returns the valve toits normally closed position when the end-gate has reached its elevatedposition.

In lowering, the same rock-shaft 3| is employed, and as it is turnedtoward the front of the truck, opens the valve 21 immediately followingthe drawing of the spring bolts 33.

The pump operates continuously until the shiftlever in the cabdisengages it through the power take-off gears.

It is understood, of course, that while this has been called anend-gate, and it is shown and described as applicable to the end of atruck, van, or other type of vehicle, it would be just as applicable toa side door as a rear end door. Also it is understood the mechanismmight be operated electrically. The only difference in the methodof-operation with an electric motor is that the control handle startsthe motor when raising the lift and automatically shuts it of! when thelimit of travel is reached, or the stops are struck) by releasing theswitch which cuts the circuit to the motor starter. When the lift isbeing lowered, the motor is not running. The operator merely valves thefluid from the cylinders by means of the control handle. It is entirelyautomatic.

We claim:

1. Mechanism of the character described comprising guide cylinders,pistons and piston rods operating therein, columns slidably connectedwith and guided by the cylinders, a sill connecting the lower ends ofthe columns, a gate connected with the sill, spring-actuated slide boltsin position to support the sill when in its elevated position, a fluidsupplysystem connected with the cylinders, a pump foreirculating thefluid, valves for controlling the direction of movement of the fluid, ashaft and connections therefrom to the valves and the bolts, and meansfor actuating the shaft whereby to release the bolts and to operate thevalves.

2. Mechanism of the character described comprising guide cylinders,pistons and piston rods operating therein, columns slidably connectedwith andguided by the cylinders, a sill connecting the lower ends of thecolumns, a gate con nected with the sill, spring-actuated slide belts inposition to support the sill when in its elevated position, a fluidsupply system connected with the cylinders, a pump forcirculating thefluid, valves for controllingthe direction of movement of the fluidpashaft and connections therefrom to the valves and the bolts, means foractuating the-shaft whereby to release the bolts and to operate thevalves, the means for actuating the bolts and valves including a rocker,a connectingrod extending therefrom to the shaft, an arm, and rodsextending from said arm to the valvestem.

3. The combination of cylinders,pistons and piston rods therein, andcolumns, the cylinders fixed and forming guides, the columns havingbrackets thereon, anti-friction rollers carried by the brackets andembracing the cylinders whereby to facilitate the movement of thecolumns with respect to the cylinders, heads secured to the columns andhaving arms which project into the cylinders in the path of the pistonswhich arms are adapted to be engaged by the piston rods and be movedthereby, and hydraulic means for controlling the movement of the pistonsand piston rods, and a gate carried by the columns.

4. The combination of a vehicle, cylinders flxed rigidly therein,pistons in the cylinders, pistonrods extending from the pistons, and thelower ends of the cylinders extending below the floor of the vehicle andcarrying anti-yfriction rollers at their lower ends, columns slidablyconnected with the cylinders and having means projecting in the path ofthe piston rods adapted to be engaged by, the latter to raise thecolumns, a

sill connected with the columns, a gate supported by the sill, ahydraulic system and valves for controlling the passageof fluidtherethrough, and means within the control of the operator for operatingthe valves.

5. The combination of a vehicle, cylinders fixed rigidly therein,pistons in the'cylinders. pistonrods extending from the pistons, and thelower ends of the cylinders extending below the floor of the vehicle,columns slidably connected with the cylinders and having meansprojecting in the path of the piston rods adapted to be engaged by thelatter to raise the columns, a sill connected with the columns,agatesupported by the sill, a hydraulic system and valves forcontrolling the passage of fluid therethroush, and means within thecontrol of the operator for operating the valves.

6. The combination of fixed cylinders, pistons and piston rods operatingtherein, a portion at.

least of the cylinders having longitudinally slotted sides, columnsguided by and movably connected with said cylinders, and having meansextending through the slots in the cylinders in the path of the pistons,whereby the columns are moved with the movement of the pistons andpiston rods, an end-gate, means for hingedly connecting the endgate withthe columns, and fluid pressure means for controlling the movement ofthe pistons and piston-rods' and the end-gate carried by the I columns.

CHARLES W; VAN BLARCOM. WILLIAM HARRIS.

